High Power Nitrogen Microwave Induced Plasma for the Determination of Some Trace Elements in Steels by Atomic Emission Spectrometry with Hydride Generation Technique

Abstract

An annular-shaped high power nitrogen microwave induced plasma (N 2 -MIP) sustained at atmospheric pressure by an Okamoto cavity has been used as a new excitation source for atomic emission spectrometry (AES). In the preliminary study of high power N 2 -MIP-AES, the background equivalent concentrations and detection limits for a number of elements were measured at the most sensitive wavelengths of the elements by using a conventional solution nebulization as a sample introduction method. The detection limits obtained for the elements of interest are inferior by approximately one to two orders of magnitude compared with those obtained in this laboratory by a conventional argon inductively coupled plasma atomic emission spectrometry with solution nebulization. Subsequently, the combination of high power N 2 -MIP-AES with continuous-flow hydride generation technique was examined for the sensitive determination of such hydride-forming elements as antimony, arsenic, selenium and tellurium. Under the optimized experimental conditions, the best attainable detection limits at Sb(I)217.581, As(I)228.812, Se(I)196.026 and Te(I)214.281 nm by use of N 2 -MIP-AES coupled with hydride generation were 4.46 ngSb/ml, 2.99 ngAs/ml, 0.86 ngSe/ml and 15.0 ngTe/ml with linear dynamic ranges of three to four orders of magnitude in concentrations. After the interference study, the present method has been applied to the determination of trace concentrations of the above-mentioned hydride-forming elements in several steel standard reference materials issued by The Japan Iron and Steel Federation. The results obtained by the proposed method were in good agreement with the certified values.